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INTRODUCTION
The Plus-X VSWR is a fully autonomous system that reduces risk to your investment in RF combiners, transmission
lines and antenna systems by fast interrupt of transmitter interlocks that prohibit RF power output. This system
simultaneously monitors forward and reflected power on up to four transmission lines and continuously updates
Voltage Standing Wave Ratio (VSWR) calculations. The Plus-X VSWR takes immediate action to interrupt
transmitter RF output if a user-defined threshold is exceeded for either reflected power or VSWR depending on
which parameter the user prioritizes for setting a fault.
Plus-X VSWR can be integrated with Arcturus or ARC Plus as well as combined with other Plus-X devices in your
system for comprehensive monitoring and remote control of your entire operation.
Even without a connection to Arcturus or ARC Plus, the Plus-X VSWR continues to provide full interrupt service.
Redundant relay outputs eliminate single point relay failures and “Three strike” logic provides quick recovery from
transient events maximizing uptime while reducing risk from actual system faults.
OPERATION OVERVIEW
CONTROL RELAYS AND INTERLOCK CIRCUITS
The Plus-X VSWR is equipped with meter inputs, a status input, and control relays that either open or close
external transmitter interlock circuits. The meter inputs are used to monitor forward and reflected power on each
transmission line (up to four lines per Plus-X VSWR). These signals are converted to power measurements via a
user calibration factor stored for each power sensor. The power measurements are used to calculate VSWR for
each transmission line.
The Plus-X VSWR can be set to monitor either reflected power or VSWR for each transmission line. If the
measured value exceeds a user defined threshold, the control relay pair assigned to that transmission line will
interrupt the interlock. The control relays can operate in normally closed or normally open configuration
depending on how the user wants to control the transmitter interlock circuit. By appropriately opening or closing
the Control Relay, the Plus-X VSWR can interrupt the RF signal flow for the affected transmission line reducing the
risk of damage to the line, antenna or other components.
CASCADED OPERATION
By enabling Cascaded Interlock Operation on one or more Plus-X VSWR units and tying together all Pin 16 Status
Inputs, for all the Plus-X VSWR units, an operator can setup the system to shut down the RF signal to all
transmission lines simultaneously if there is a single fault detected. Cascaded operation is useful in situations
where multiple transmitters feed a combiner and a single fault downstream of the combiner output could
damage one or more of them.
